All posts by William Sescu

Consultant

William Sescu has more than 17 years of IT experience, more than ten years in Oracle and Unix Consulting. He is specialized in Oracle Database High Availability, RAC Clusters, DataGuard, Backup/Recovery and Database Migrations. Besides that, he is also specialized in different Unix flavours, especially in Linux and Solaris, and also in virtualization technologies like VMware and Solaris Containers.
In the OpenSource world, William Sescu is specialized in the areas of MySQL/MariaDB and Galera Clusters. William Sescu also is a Trainer for different disciplines like “Linux for Oracle DBS’s”, “Oracle RMAN”, “Oracle Flashback Techniques” and many more.
Prior to joining dbi services, William Sescu was working as an Oracle Database Administrator for Amadeus Data Processing in Germany.
William Sescu has two Oracle Master Degrees, one in Oracle 12c and one in Oracle 11g, and several Oracle Certified Expert certifications.
Besides that, William Sescu is OCM MAA 12c. A certification, that only a few people worldwide have.

By accident, it could happen that someone dropped an OUD entry in your replicated environment and of course, the entry is deleted on all replicas as well. And besides that, you got no logical ldif export of your OUD. Not a good situation, but if you have a done regular backups, there is a way out without resetting the whole OUD environment to an old timestamp. The idea is, to create a second empty OUD…

A lot of possibilities exist to migrate MySQL to MariaDB. In this blog I would like to show a scenario where I migrate MySQL 5.7.19 with a lot of databases to MariaDB 10.2.7, which is on a different host. The tools I am using are mydumper/myloader and ncat. Please be aware that mydumper does not come out of the box. It has to be installed beforehand, like explained in my previous blog: https://blog.dbi-services.com/mariadb-speed-up-your-logical-mariadb-backups-with-mydumper/ The same…

Per default, MariaDB is shipped with a utility called mysqldump for logical backups. For more information, please take a look at the following link. https://mariadb.com/kb/en/mariadb/mysqldump/ The mysqldump has advantages, e.g. it is easy to use and it is shipped with the standard MariaDB installation. So, no additional installation is needed. However, it has also some disadvantages. E.g. it is single threaded and it is writing to one big file, even with the latest version which…

A new OUD bundle patch was release at the 18th of July 2017, and this gives me the opportunity to show how fast an OUD can be patched, if configured correctly. In case you have an OUD multi master replication with a load balancer virtual IP on top, then zero downtime patching is possible. This is the configuration that I usually recommend. Not only for high availability, but also for maintenance. A typical OUD installation…

The ODSM is a quite powerful tool for managing the Oracle Unified Directory, and quite a lot of default settings are very reasonable. But there is one that disturbed me from the beginning. It is the ODSM Session Timeout. You might see a message like the following. Or maybe this one. It just says, that the page will expire unless a response is received within 2 minutes. Doing some complex searches or similar stuff often…

One of the questions that pops up immediately, after you have installed your OUD successfully is how to integrate it into the automatic startup routines of the OS. My example here show how to do it on Oracle Linux 6. On Oracle Linux 7 it looks a little different. Fortunately, Oracle delivers a script called “create-rc-script”, which can be found in your asinst home directory. It lets you specify the user name under which the…

My blog about listener rotation caused some discussion, which is great. It sounds like an easy stuff, but in case of listener logging it isn’t. https://blog.dbi-services.com/oracle-12-2-how-to-rotate-the-12-2-listener-log-diag_adr_enabled_listener-off/ Many ways do exist to rotate the listener log, but I was trying to point out some issues, because there are a few, e.g. What happens when the log file reaches 4G? What are the performance implications? What happens if I move the listener.log while the listener is running…

Nowadays, since the cloud is becoming more and more important, the PL/SQL API’s become more and more important too. Fortunately, Oracle has quite a lot of them. E.g. How do you run a Data Pump export if you have no ssh connectivity to the server? You could use the old exp tool, which is still available even with Oracle 12.2, or you can use DBMS_DATAPUMP. The Data Pump API is quite good documented in the…

The listener log file contains a lot of very useful information, like the program which was used for the connection, the IP address where the connection is coming from, the OS user which was used on the client and many many more. 05-JUN-2017 12:36:19 * service_update * DBIT122 * 0 05-JUN-2017 12:36:19 * (CONNECT_DATA=(SERVICE_NAME=DBIT122_SITE1_DGMGRL)(UR=A)(CID=(PROGRAM=sqlplus@dbidg01)(HOST=dbidg01)(USER=oracle))) * (ADDRESS=(PROTOCOL=tcp)(HOST=192.168.56.201)(PORT=42619)) * establish * DBIT122_SITE1_DGMGRL * 0 05-JUN-2017 12:36:19 * (CONNECT_DATA=(SERVICE_NAME=DBIT122_SITE1_DGMGRL)(UR=A)(CID=(PROGRAM=sqlplus@dbidg01)(HOST=dbidg01)(USER=oracle))) * (ADDRESS=(PROTOCOL=tcp)(HOST=192.168.56.201)(PORT=42620)) * establish * DBIT122_SITE1_DGMGRL * 0 However,…